1. Technical Field
The present invention relates to dark field illumination as is widely used in machine vision to detect features higher or lower than regular surfaces.
2. Background Information
Over the past several decades, the semiconductor has exponentially grown in use and popularity. The semiconductor has in effect revolutionized society by introducing computers, electronic advances, and generally revolutionizing many previously difficult, expensive and/or time consuming mechanical processes into simplistic and quick electronic processes. This boom in semiconductors has been fueled by an insatiable desire by business and individuals for computers and electronics, and more particularly, faster, more advanced computers and electronics whether it be on an assembly line, on test equipment in a lab, on the personal computer at one's desk, or in the home electronics and toys.
The manufacturers of semiconductors have made vast improvements in end product quality, speed and performance as well as in manufacturing process quality, speed and performance. However, there continues to be demand for faster, more reliable and higher performing semiconductors.
Processors who are building semiconductors and like microelectronics must be able to provide ample illumination for the machine vision process. Users of inspection equipment continue to demand smaller, more intense, more robust illumination.
In the past, it was typical to use halogen, laser or other illumination methods rather than fiber optic. Where fiber optic has been tried, the setup has typically involved using a metal ring with a polished surface attached to standard fiber optic ring light to achieve some dark field illumination.